Particle Discharge Characteristics from a Nozzle of Thin Tube Immersed in Liquid Subject to Ultrasonic Wave Force

Abstract

A wet micro-feeder that utilized ultrasonic wave force was designed and constructed to feed small particles into a container of wet particulate materials. The particle discharge characteristics from a nozzle with the inside diameter, D_n, were experimentally investigated using spherical and irregular particles of 80 to 180μm in diameter, d_p. As a result, the critical ratio for particle blockage of present feeder, (D_n/d_p)_c≈3.0, was smaller than the values obtained previously (>4-5) in the gravitational field for dry powders. The present feeder could achieve stable and continuous discharge of small amount of particles. Multiple regression analysis proved that the discharge rate of particles, i. e. the number of particles discharged from a nozzle per unit time, N, depended on D_n, d_p, the applied voltage V₀, and the median value of particle shape index (surface roughness), φ₅₀, and that N was proportional to D^2.29_n. Therefore, N could be controlled by V₀ and D_n for given particles.